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Sleep-laughing – Hypnogely

Published online by Cambridge University Press:  23 September 2014

Nikola N. Trajanovic*
Sleep Research Unit, University Health Network Neurophysiology Unit, Polyclinic ‘Dr. Ristic’
Colin M. Shapiro
Sleep Research Unit, University Health Network Department of Psychiatry, University of Toronto, Toronto, Canada
Srdjan Milovanovic
School of Medicine, Belgrade University Clinic for Psychiatry, Clinical Centre of Serbia, Belgrade, Serbia
Sleep Research Unit, UHN TWH MedWest, 221-750 Dundas St. W., Toronto, Ontario, M6J 3S3, Canada. Email:
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To explain relatively common phenomenon of laughing during sleep and help to better define criteria for differentiating between physiological and pathological sleep-laughing.


Observational study of patients who underwent a sleep assessment in a referential tertiary health facility.


A total of ten patients exhibited sleep laughing, nine of whom had episodes associated with rapid eye movement (REM) sleep. Also, in one of the patients sleep-laughing was one of the symptoms of REM sleep Behaviour Disorder, and in another patient sleep-laughing was associated with NREM sleep arousal parasomnia.


The collected data and review of literature suggests that hypnogely in majority of the cases presents as a benign physiological phenomenon related to dreaming and REM sleep. Typically, these dreams are odd, bizarre or even unfunny for a person when awake. Nevertheless, they bring a sense of mirth and a genuine behavioural response. In a minority of cases, sleep-laughing appears to be a symptom of neurological disorders affecting the central nervous system. In these patients the behavioural substrate differs when compared to physiological laughing, and the sense of mirth is usually absent.

Research Article
Copyright © The Canadian Journal of Neurological 2013


1. Freud, S. Interpretation of dreams. London: Lowe and Brydone Ltd.; 1954. p. 472.Google Scholar
2. Grotjahn, M. Laughter in dreams. Psychoanal Q. 1945;14:221–7.CrossRefGoogle Scholar
3. Arkin, AM. Sleep-talking: psychology and psychophysiology. Hillsdale: Lawrence Erlbaum Associates, Inc.; 1981.Google Scholar
4. Trajanovic, NN, Shapiro, CM. Sleep-laughing (somnorismus). Sleep. 2005; vol. 28: A260.Google Scholar
5. Kales, A, Hoedemaker, FS, Jacobson, A, Kales, JD, Paulson, MJ, Wilson, TE. Mentation during sleep: REM and NREM recall reports. Percept Mot Skills. 1967;24(2):555–60.CrossRefGoogle ScholarPubMed
6. Nielsen, TA. A review of mentation in REM and NREM sleep: “covert” REM sleep as a possible reconciliation of two opposing models. Behav Brain Sci. 2000;23(6):851–66.CrossRefGoogle ScholarPubMed
7. McNamara, P, Johnson, P, McLaren, D, Harris, E, Beauharnais, C, Auerbach, S. REM and NREM sleep mentation. Int Rev Neurobiol. 2010;92:6986.CrossRefGoogle ScholarPubMed
8. Takeuchi, T, Miyasita, A, Inugami, M, Yamamoto, Y. Intrinsic dreams are not produced without REM sleep mechanisms: evidence through elicitation of sleep onset REM periods. J Sleep Res. 2001;Mar;10(1):4352.CrossRefGoogle Scholar
9. Mahon, EJ. A joke in a dream. A note on the complex aesthetics of disguise. Psychoanal Study Child. 2002;57:452–7.CrossRefGoogle Scholar
10. Fisher, BE, Pauley, C, McGuire, KD. Children’s sleep behavior scale: Normative data on 870 children in grades 1 to 6. Percept Mot Skills. 1989;68(1):227–36.CrossRefGoogle Scholar
11. Nielsen, T, Svob, C, Kuiken, D. Dream-enacting behaviors in a normal population. Sleep. 2009;Dec;32(12):1629–36.CrossRefGoogle Scholar
12. Schenck, CH, Bundlie, SR, Patterson, AL, Mahowald, MW. Rapid eye movement sleep behavior disorder: a treatable parasomnia affecting older adults. JAMA. 1987;257(13):1786–9.CrossRefGoogle ScholarPubMed
13. Schenck, CH, Hurwitz, TD, Mahowald, MW. REM sleep behavior disorder: an update on a series of 96 patients and a review of the world literature. J Sleep Res. 1993;2:224–31.CrossRefGoogle Scholar
14. Siclari, F, Wienecke, M, Poryazova, R, Bassetti, CL, Baumann, CR. Laughing as a manifestation of rapid eye movement sleep behavior disorder. Parkinsonism Relat Disord. 2011;17(6): 382–5.CrossRefGoogle ScholarPubMed
15. Iranzo, A, Santamaria, J, Tolosa, E. The clinical and pathophysiological relevance of REM sleep behavior disorder in neurodegenerative diseases. Sleep Med Rev. 2009;13(6):385401.CrossRefGoogle ScholarPubMed
16. Parvizi, J, Arciniegas, DB, Bernardini, GL, et al. Diagnosis and management of pathological laughter and crying. Mayo Clin Proc. 2006;81:1482–6.CrossRefGoogle ScholarPubMed
17. Wortzel, HS, Oster, TJ, Anderson, CA, Arciniegas, DB. Pathological laughing and crying: epidemiology, pathophysiology and treatment. CNS Drugs. 2008;22(7):531–45.CrossRefGoogle ScholarPubMed
18. Parvizi, J, Coburn, KL, Shillcutt, SD, Coffey, CE, Lauterbach, EC, Mendez, MF. Neuroanatomy of pathological laughing and crying: a report of the American Neuropsychiatric Association Committee on Research. J Neuropsychiatry Clin Neurosci. 2009;Winter;21(1):7587.CrossRefGoogle ScholarPubMed
19. De Barros-Ferreira, M, Chodkiewicz, JP, Lairy, GC, Salzarulo, P. Disorganized relations of tonic and phasic events of REM sleep in a case of brain-stem tumour. Electroencephalogr Clin Neurophysiol. 1975;38(2):203–7.CrossRefGoogle Scholar
20. Achari, AN, Colover, J. Posterior fossa tumors with pathological laughter. JAMA. 1976;235:1469–71.CrossRefGoogle ScholarPubMed
21. Lal, AP, Chandy, MJ. Pathological laughter and brain stem glioma. J Neurol Neurosurg Psychiatry. 1992;55(7):628–9.CrossRefGoogle ScholarPubMed
22. Matsuoka, S, Yokota, A, Yasukouchi, H, et al. Clival chordoma associated with pathological laughter. Case report. J Neurosurg. 1993;79(3):428–33.Google ScholarPubMed
23. Bhatjiwale, MG, Goel, A, Desai, K. Pathological laughter as a presenting symptom of trigeminal neurinoma-case report. Neurol Med Chir (Tokyo). 1996;36(9):644–6.CrossRefGoogle ScholarPubMed
24. Nadkarni, TD, Goel, A. Trochlear nerve neurinoma presenting as pathological laughter. Br J Neurosurg. 1999;13(2):212–3.CrossRefGoogle ScholarPubMed
25. Machado, AG, Aguiar, PH, Marino, R Jr. Pathological laughter in a patient with trigeminal neurinoma. Arq Neuropsiquiatr. 2002;60(4):1000–2.CrossRefGoogle Scholar
26. Jagetia, A, Pratap Kumar, N, Singh, D, Sinha, S. Pathological laughter in trigeminal schwannoma: case report and review of the literature. Neurosurg Rev. 2006;(4):348–52; discussion 352.CrossRefGoogle ScholarPubMed